US3779921A - Synthetic aircraft turbine oil - Google Patents
Synthetic aircraft turbine oil Download PDFInfo
- Publication number
- US3779921A US3779921A US00282182A US3779921DA US3779921A US 3779921 A US3779921 A US 3779921A US 00282182 A US00282182 A US 00282182A US 3779921D A US3779921D A US 3779921DA US 3779921 A US3779921 A US 3779921A
- Authority
- US
- United States
- Prior art keywords
- lubricating oil
- oil composition
- percent
- composition according
- thiazolidinedione
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D263/00—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings
- C07D263/02—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings not condensed with other rings
- C07D263/30—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members
- C07D263/34—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
- C07D263/44—Two oxygen atoms
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D263/00—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings
- C07D263/02—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings not condensed with other rings
- C07D263/30—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members
- C07D263/34—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
- C07D263/46—Sulfur atoms
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D277/00—Heterocyclic compounds containing 1,3-thiazole or hydrogenated 1,3-thiazole rings
- C07D277/02—Heterocyclic compounds containing 1,3-thiazole or hydrogenated 1,3-thiazole rings not condensed with other rings
- C07D277/20—Heterocyclic compounds containing 1,3-thiazole or hydrogenated 1,3-thiazole rings not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members
- C07D277/32—Heterocyclic compounds containing 1,3-thiazole or hydrogenated 1,3-thiazole rings not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
- C07D277/34—Oxygen atoms
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M3/00—Liquid compositions essentially based on lubricating components other than mineral lubricating oils or fatty oils and their use as lubricants; Use as lubricants of single liquid substances
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
- C10M2207/02—Hydroxy compounds
- C10M2207/023—Hydroxy compounds having hydroxy groups bound to carbon atoms of six-membered aromatic rings
- C10M2207/025—Hydroxy compounds having hydroxy groups bound to carbon atoms of six-membered aromatic rings with condensed rings
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
- C10M2207/28—Esters
- C10M2207/281—Esters of (cyclo)aliphatic monocarboxylic acids
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
- C10M2207/28—Esters
- C10M2207/282—Esters of (cyclo)aliphatic oolycarboxylic acids
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
- C10M2207/28—Esters
- C10M2207/283—Esters of polyhydroxy compounds
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
- C10M2207/28—Esters
- C10M2207/286—Esters of polymerised unsaturated acids
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2215/00—Organic non-macromolecular compounds containing nitrogen as ingredients in lubricant compositions
- C10M2215/02—Amines, e.g. polyalkylene polyamines; Quaternary amines
- C10M2215/06—Amines, e.g. polyalkylene polyamines; Quaternary amines having amino groups bound to carbon atoms of six-membered aromatic rings
- C10M2215/064—Di- and triaryl amines
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2219/00—Organic non-macromolecular compounds containing sulfur, selenium or tellurium as ingredients in lubricant compositions
- C10M2219/09—Heterocyclic compounds containing no sulfur, selenium or tellurium compounds in the ring
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2219/00—Organic non-macromolecular compounds containing sulfur, selenium or tellurium as ingredients in lubricant compositions
- C10M2219/10—Heterocyclic compounds containing sulfur, selenium or tellurium compounds in the ring
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2219/00—Organic non-macromolecular compounds containing sulfur, selenium or tellurium as ingredients in lubricant compositions
- C10M2219/10—Heterocyclic compounds containing sulfur, selenium or tellurium compounds in the ring
- C10M2219/102—Heterocyclic compounds containing sulfur, selenium or tellurium compounds in the ring containing sulfur and carbon only in the ring
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2219/00—Organic non-macromolecular compounds containing sulfur, selenium or tellurium as ingredients in lubricant compositions
- C10M2219/10—Heterocyclic compounds containing sulfur, selenium or tellurium compounds in the ring
- C10M2219/104—Heterocyclic compounds containing sulfur, selenium or tellurium compounds in the ring containing sulfur and carbon with nitrogen or oxygen in the ring
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2219/00—Organic non-macromolecular compounds containing sulfur, selenium or tellurium as ingredients in lubricant compositions
- C10M2219/10—Heterocyclic compounds containing sulfur, selenium or tellurium compounds in the ring
- C10M2219/104—Heterocyclic compounds containing sulfur, selenium or tellurium compounds in the ring containing sulfur and carbon with nitrogen or oxygen in the ring
- C10M2219/106—Thiadiazoles
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2223/00—Organic non-macromolecular compounds containing phosphorus as ingredients in lubricant compositions
- C10M2223/02—Organic non-macromolecular compounds containing phosphorus as ingredients in lubricant compositions having no phosphorus-to-carbon bonds
- C10M2223/04—Phosphate esters
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2223/00—Organic non-macromolecular compounds containing phosphorus as ingredients in lubricant compositions
- C10M2223/02—Organic non-macromolecular compounds containing phosphorus as ingredients in lubricant compositions having no phosphorus-to-carbon bonds
- C10M2223/04—Phosphate esters
- C10M2223/041—Triaryl phosphates
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2223/00—Organic non-macromolecular compounds containing phosphorus as ingredients in lubricant compositions
- C10M2223/02—Organic non-macromolecular compounds containing phosphorus as ingredients in lubricant compositions having no phosphorus-to-carbon bonds
- C10M2223/04—Phosphate esters
- C10M2223/042—Metal salts thereof
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2229/00—Organic macromolecular compounds containing atoms of elements not provided for in groups C10M2205/00, C10M2209/00, C10M2213/00, C10M2217/00, C10M2221/00 or C10M2225/00 as ingredients in lubricant compositions
- C10M2229/04—Siloxanes with specific structure
- C10M2229/041—Siloxanes with specific structure containing aliphatic substituents
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
- C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
- C10N2030/08—Resistance to extreme temperature
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
- C10N2040/00—Specified use or application for which the lubricating composition is intended
- C10N2040/12—Gas-turbines
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
- C10N2040/00—Specified use or application for which the lubricating composition is intended
- C10N2040/12—Gas-turbines
- C10N2040/13—Aircraft turbines
Definitions
- This invention is concerned with a lubricating oil composition for gas turbine or jet engines.
- Gas turbine engines employed in aircraft are operated under extreme environmental conditions.
- the lubricating oil must be fluid under sub-zero temperatures and must be thermally stable, non-corrosive and possess loadcarrying and anti-wear properties at engine temperatures of 400 to 500F. or above.
- the environmental and operating conditions put such a severe stress on the lubricating oil for a turbine engine that the most advanced mineral lubricating oil compositions cannot be employed in these engines.
- the ester-base oils are operative over a wide temperature range and exhibit good thermal stability, anti-wear, and oxidation-resistant properties while providing effective lubrication.
- U.S. Pat. No. 2,796,403 discloses grease and lubricating oil compositions including synthetic lubricants having extreme pressure properties containing three-hydrocarbon-substituted rhodanines.
- U.S. Pat. No. 2,796,404 discloses lubricating oil compositions including synthetic lubricants of the ester or ether type having extreme pressure and anti-corrosive properties containing alkylaminobenzylidenerhodanine.
- the synthetic lubricating oil composition of the invention comprises a major portion of an aliphatic esterbase oil having lubricating properties formed from the reaction of a pentaerythritol or trimethylolpropane and a mixture of hydrocarbyl monocarboxylic acids containing an effective load-carrying amount of a thiooxazolidinedione, thiazolidinedione or corresponding amine salt represented by the formulas:
- the compounded fluid will also contain an alkylphenyl or alkarylphenyl naphthylamine, a dialkyldiphenylamine. a polyhydroxyanthraquinone and a hydrocarbyl phosphate defined below.
- R is a hydrocarbyl radical having from about four to 24 carbon atoms.
- the preferred amine salts are those in which R is an alkyl or aliphatic radical having from about 12 to 22 carbon atoms with the most preferred being those in which R is an aliphatic radical having from about 18 to about 22 carbon atoms.
- Examples of other compounds within the prescribed classes which can be employed in the synthetic aircraft turbine oil composition of this invention include the following: n-Butyl, n-hexyl, Z-ethylhexyl, n-decyl-, 1 or 2-naphthyl,-tris-(2-ethylhexyl)amine salts of thiooxazolidinediones or thiazolidinediones, the benzylidene, S-heptylidene etc. derivatives of thiooxazolidinedione or thiazolidinediones and their amine salts and the -benzyl, S-phenyl, S-methyl etc. derivatives and amine salts of these materials can be used.
- the prescribed compounds are employed in the lubricating oil composition in an amount ranging from about 0.01 to 5 weight percent. In general, amounts ranging from about 0.05 to 0.5 percent are effective and are preferred for imparting load-carrying and corrosion resistance properties to the lubricant compositron.
- the base fluid component of the lubricant of the invention is an ester-base fluid prepared from pentaerythritol or trimethylolpropane and a mixture of hydrocarbyl monocarboxylic acids.
- Ester-base fluid prepared from pentaerythritol or trimethylolpropane and a mixture of hydrocarbyl monocarboxylic acids.
- Polypentaerythritols such as dipentaerythritol, tripentaerythritol and tetrapentaery-thritol can also be employed in the reaction to prepare the base oil.
- the hydrocarbon monocarboxylic acids which are used to form the ester-base fluid include the straightchain and branched-chain aliphatic acids, cy'cloali phatic acids and aromatic acids, as well as mixtures of these acids.
- the acids employed have from about two to about 18 carbon atoms per molecule, and preferably from about five to 10 carbon atoms.
- suitable specific acids are acetic, propionic, butyric, valeric, isovaleric, caproic, decanoic, hexadecanoic, pelargonic, dodecanoic, cyclohexanoic, naphthenic, tertiary-butylacetic acid and 2-ethylhexanoic acid.
- the acids are reacted in proportions leading to a completely esterified pentaerythritol or trimethylolpropane with the preferred ester bases being the pentaerythritol tetraesters.
- the preferred ester bases being the pentaerythritol tetraesters.
- examples of such commercially available tetraesters include pentaerythritol tetracaproate, which is prepared from purified pentaery-thritol and crude caproic acid containing other C monobasic acids.
- Another suitable tetraester is prepared from a technical grade pentaerythritol and a mixture of acids comprising about percent valeric, 12 percent Z-methyl pentanoic, 27 percent caprylic, 15 percent pelargonic, 9 percent heptylic, 5 percent caproic and minor amounts of iso-valeric and capric acids.
- Another effective ester is the triester of trimethylolpropane in which the trimethylolpropane is esterified with a mono-basic acid mixture consisting of 2 percent valeric, 9 percent caproic, 13 percent heptanoic, 7 percent octanoic, 3 percent caprylic, percent pelargonic and 1 percent capric acids.
- Trimethylolpropane triheptanoate, trimethylolpropanepentanoate and trimethylolpropanehexanoate are also suitable.
- the ester base comprises the major portion of the formulated synthetic ester-base lubricating oil composition.
- this ester-base fluid is present in a concentration ranging from about to 98 percent of the composition.
- Alkyl or alkaryl phenyl naphthylamines are highly effective anti-oxidants for synthetic lubricating oils. These compounds are represented by the formula:
- ditive is an amount from about 0.5 to 2.5 weight percent.
- R is an alkyl radical having from about four to 12 carbon atoms.
- these amines include dioctyldiphenylamine didecyldiphenylamine, didodecyldiphenylamine, dihexydiphenylamine and similar compounds. Dioctyldiphenylamine is the preferred compound and the preferred concentration is from about 0.5 to 2.0 percent.
- An effective metal deactivator for a synthetic lubricating oil composition is a polyhydroxyanthraquinone.
- Suitable compounds in this class are the dior polyhydroxy-anthraquinones, such as 1,4-dihydroxyanthraquinone, also known as quinizarin, 1,5-dihydroxyanthraquinone and 1,S-di-hydroxyanthraquinone, and the higher polyhydroxyanthraquinones.
- the preferred concentration of this component is from about 0.01 to 0.5 weight percent.
- a valuable anti-wear component for a synthetic lubricating oil composition is a hydrocarbylphosphate ester, represented by the formula (RO) -,PO, in which R is a hydrocarbyl radical having from two to 12 carbon atoms.
- the hydrocarbyl radical can be an alkyl, aryl, alkaryl, cycloalkyl or aralkyl radical of the prescribed carbon chain length, although radicals having from four to 8 carbon atoms are preferred.
- Effective compounds include tricresyl phosphate, cresyl di-phenyl phosphate, triphenylphosphate, tributylphosphate, tris- (2-ethylhexyl) phosphate and tricyclohexylphosphate. These compounds are generally employed in a lubricating oil composition in a concentration ranging from about 0.5 to 5 percent.
- an anti-foam additive in the synthetic lubricating oil composition.
- Effective anti-foamants are the silicone fluids, such as dimethyl silicone and diethylsilicone and these are generally employed at a concentration ranging from about 5 to 200 ppm parts per million.
- the lubricating oil composition of the invention was tested for its load-carrying properties in the Ryder Gear Test. This test was conducted in accordance with Federal Test Method Standard 791, Test Method 6508.
- the base fluid blend employed for conducting the tests consisted of a commercial ester base from pentaerythritol and a mixture of C to C fatty acids containing 0.10 weight percent quinizarin, 1.00 weight percent p,- p'-di-tert.-octyldiphenylamine, 1.50 weight percent N- (4-tert.-octylphenyl)-l-naphthylamine, 2.00 weight percent tricresyl phosphate and 50 ppm of a dimethyl silicone fluid.
- a synthetic lubricating oil composition comprising a major portion of an aliphatic ester-base oil having lubricating properties formed from the reaction of a pentaerythritol or trimethylolpropane and a saturated hydrocarbyl monocarboxylic acid having from about 2 to 18 carbon atoms per molecule containing from about 0.01 to 5 weight percent of an oxazolidinedione, thiazolidinedione or the corresponding amine salt represented by the formulas:
- X represents S when Y is O
- X represents 0 when Y is S
- R represents a hydrocarbyl radical having from about four to 24 carbon atoms.
- a lubricating oil composition according to claim 1 containing from about 0.05 to 0.5 weight percent of said thio-oxazolidinedione, thiazolidinedione or corresponding amine salt.
- a lubricating oil composition according to claim 1 containing 2-thio-oxazolidinedione.
- a lubricating oil composition according to claim 1 containing a 2,4-thiazolidinedione.
- a lubricating oil composition according to claim 1 containing the tC, C primary amine salt of 2,4- thiazolidinedione.
- a lubricating oil composition according to claim 1 containing the tC, C alkyl primary amine salt of 2-thio-oxazolidinedione.
- a lubricating oil composition according to claim 1 containing from about 0.5 to 2.5 percent of an alkylphenyl naphthylamine, from about 0.5 to 2.0 percent of dialkyldiphenylamine, from about 0.01 to 0.5 percent of a polyhydroxyanthraquinone and from about 0.5 to 5 percent of a hydrocarbyl phosphate ester.
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Lubricants (AREA)
Abstract
Synthetic lubricating oil composition comprising a major portion of an aliphatic ester-base oil having lubricating properties formed from the reaction of a pentaerythritol or trimethylolpropane and an organic monocarboxylic acid containing a thio-oxazolidinedione, a thiazolidinedione or the corresponding amine salt.
Description
United States Patent Patmore et al.
[ Dec. 18, 1973 SYNTHETIC AIRCRAFT TURBINE OIL Inventors: Edwin L. Patmore, Fishkill;
Frederick G. Oberender, Wappingers Falls; David D. Reed, Lagrangeville, all of NY.
Assignee: Texaco Inc., New York, NY.
Filed: Aug. 21, 1972 Appl. No.1 282,182
US. Cl 252/33.6, 252/4715,'252/402, 260/307 C Int. Cl. C10m l/38, ClOm l/32 Field of Search 252/336, 56 S, 47.5, 252/402; 260/307 C References Cited UNITED STATES PATENTS 6/1957 Kluge et a1 252/475 6/1957 Watson et a1... 252/47.5 6/1957 Levin 252/475 2,800,491 7/1957 Ellis r ..252/47 5 3,249,543 5/1966 Wilson ..252/47.5
FOREIGN PATENTS OR APPLICATIONS 1,180,387 2/1970 Great Britain OTHER PUBLlCATlONS Cohen Ind. Eng. Chem. Vol. 45 (1953), pages 1766-1774.
Primary ExaminerDaniel E. Wyman Assistant ExaminerW. Cannon 1 Attorney-Thomas H. Whaley et a1.
10 Claims, No Drawings SYNTHETIC AIRCRAFT TURBINE OIL BACKGROUND OF THE INVENTION This invention is concerned with a lubricating oil composition for gas turbine or jet engines. Gas turbine engines employed in aircraft are operated under extreme environmental conditions. The lubricating oil must be fluid under sub-zero temperatures and must be thermally stable, non-corrosive and possess loadcarrying and anti-wear properties at engine temperatures of 400 to 500F. or above. The environmental and operating conditions put such a severe stress on the lubricating oil for a turbine engine that the most advanced mineral lubricating oil compositions cannot be employed in these engines. It is conventional to employ synthetic ester-base lubricating oil compositions containing suitable augmenting additive combinations for lubricating turbine engines. The ester-base oils are operative over a wide temperature range and exhibit good thermal stability, anti-wear, and oxidation-resistant properties while providing effective lubrication.
Newer and more powerful gas turbine engines designed to provide advanced levels of supersonic flight are under development. These engines put increasing stresses on the lubricating oil composition and improved oil compositions must be provided to meet the load-carrying, anti-wear, oxidation resistance and corrosion resistance requirements at higher levels of oxidative and thermal stress.
DESCRIPTION OF THE PRIOR ART U.S. Pat. No. 2,796,402 discloses grease and lubricating oil compositions having extreme pressure properties containing rhodanine and its five-substituted compounds.
U.S. Pat. No. 2,796,403 discloses grease and lubricating oil compositions including synthetic lubricants having extreme pressure properties containing three-hydrocarbon-substituted rhodanines.
U.S. Pat. No. 2,796,404 discloses lubricating oil compositions including synthetic lubricants of the ester or ether type having extreme pressure and anti-corrosive properties containing alkylaminobenzylidenerhodanine.
SUMMARY OF THE INVENTION The synthetic lubricating oil composition of the invention comprises a major portion of an aliphatic esterbase oil having lubricating properties formed from the reaction of a pentaerythritol or trimethylolpropane and a mixture of hydrocarbyl monocarboxylic acids containing an effective load-carrying amount of a thiooxazolidinedione, thiazolidinedione or corresponding amine salt represented by the formulas:
in which X represents sulfur when Y represents oxygen. and X represents oxygen when Y represents sulfur, and R represents a hydrocarbyl radical having from about four to 24 carbon atoms. In general, the compounded fluid will also contain an alkylphenyl or alkarylphenyl naphthylamine, a dialkyldiphenylamine. a polyhydroxyanthraquinone and a hydrocarbyl phosphate defined below.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Thio-oxazolidinedione and thiazolidinedione suitable for the synthetic lubricating oil composition are represented by the following formula:
in which X is sulfur when Y represents oxygen, and X is oxygen when Y represents sulfur. The corresponding amine salts have the formula:
where X and Y have the same values and R is a hydrocarbyl radical having from about four to 24 carbon atoms. The preferred amine salts are those in which R is an alkyl or aliphatic radical having from about 12 to 22 carbon atoms with the most preferred being those in which R is an aliphatic radical having from about 18 to about 22 carbon atoms.
Methods for preparing the prescribed thio-oxazolidinedione, thiazolidinedione and the corresponding amine salts are well known. The preparation of 2,4- oxazolidine-dione is described in Chemical Abstracts, 50, 9387,, and in J. Am. Chem. Soc., 80,973 (1958).
The following examples illustrate the preparation of a representative number of the prescribed compounds which can be employed in the synthetic aircraft turbine oil compositions of this invention.
EXAMPLE I 2Thi0-Oxazolidinedione Formaldehyde (40 mls. of a 37 percent solution) was added with stirring and cooling (temperature held at 10C.) to a solution of sodium thiocyanate (40.5 g.) and sodium cyanide (27.0 g.) in water (55 mls.). Concentrated hydrochloric acid was added while maintaining the temperature at 10C. The reactants were allowed to warm to room temperature and set overnight. Solids were removed by filtration and the filtrate was heated at reflux for 1.5 hours. Extraction with ether (5 X ml.), concentration on the rotary evaporator, and two recrystallizations from water gave 7.] g. of product, m.p. l079C. (lit. m.p. l 13C.).
EXAMPLE ll 2,4-Thiazolidinedione A reaction mixture of pseudothiohydantoin (6.4 g.) and hydrochloric acid (50 ml. conc. HCl/lSO mls. of water) was heated at reflux for 6 hours, concentrated on the rotary evaporator, and treated with 50 mls. of methanol. The ammonium chloride was removed by filtration and the filtrate concentrated to give 5.4 g. of crude product. Recrystallization from ethanol gave 4.2 g. of product, m.p. l24126C. (lit. m.p. l26,l27C.).
EXAMPLE III 2,4-Oxazolidinedione A sodium ethoxide solution was prepared from sodium (9.2 g.) and anhydrous ethanol (200 mls.). This solution was cooled while ethyl glycolate (41.6 g.) and urea (24.0 g.) were added. The reaction mixture was heated to reflux and held there 15 minutes before concentration on the rotary evaporator. The solid residue was dissolved in 120 mls. of water and the aqueous solution extracted with 75 mls. of ether. The aqueous solution'was then acidified, extracted with four 75 ml. portions of ether, the ether extracts combined and concentrated on the rotary evaporator to yield the crude product. Recrystallization from ethanol afforded 5.3 g. of product, m.p. 8788C. (lit. m.p. 89-90C.).
EXAMPLE IV t'C18-C22'Alky1 Primary Thiazolidinedione t-C -C Primary amine (31.5 g.) was added to a stirred solution of 2,4-thiazolidinedione (11.7 g.) in benzene (7O mls.) and the reactants were heated at 50C. for 1 hour. The reaction mixture was concentrated on the rotary evaporator at 165F. and aspirator pressure and then under vacuum pump pressure to give 41.5 g. of product. Neut. No. 134 (calc. 130).
EXAMPLE V Primary Amine Salt of 2-Thio- Amine Salt of 2,4-
t-C -C Alkyl Oxazolidinedione t-C -C Alkyl primary amine (21.4 g.) and 2-thiooxazolidinedione (8.0 g.) were heated together in benzene (50 mls.) for 1 hour at 50C. Concentration on the rotary evaporator at 165F. at vacuum pump pressures gave 29 g. of product. Neut. No. 120 (calc. 129).
Examples of other compounds within the prescribed classes which can be employed in the synthetic aircraft turbine oil composition of this invention include the following: n-Butyl, n-hexyl, Z-ethylhexyl, n-decyl-, 1 or 2-naphthyl,-tris-(2-ethylhexyl)amine salts of thiooxazolidinediones or thiazolidinediones, the benzylidene, S-heptylidene etc. derivatives of thiooxazolidinedione or thiazolidinediones and their amine salts and the -benzyl, S-phenyl, S-methyl etc. derivatives and amine salts of these materials can be used.
The prescribed compounds are employed in the lubricating oil composition in an amount ranging from about 0.01 to 5 weight percent. In general, amounts ranging from about 0.05 to 0.5 percent are effective and are preferred for imparting load-carrying and corrosion resistance properties to the lubricant compositron.
The base fluid component of the lubricant of the invention is an ester-base fluid prepared from pentaerythritol or trimethylolpropane and a mixture of hydrocarbyl monocarboxylic acids. Polypentaerythritols, such as dipentaerythritol, tripentaerythritol and tetrapentaery-thritol can also be employed in the reaction to prepare the base oil.
The hydrocarbon monocarboxylic acids which are used to form the ester-base fluid include the straightchain and branched-chain aliphatic acids, cy'cloali phatic acids and aromatic acids, as well as mixtures of these acids. The acids employed have from about two to about 18 carbon atoms per molecule, and preferably from about five to 10 carbon atoms. Examples of suitable specific acids are acetic, propionic, butyric, valeric, isovaleric, caproic, decanoic, hexadecanoic, pelargonic, dodecanoic, cyclohexanoic, naphthenic, tertiary-butylacetic acid and 2-ethylhexanoic acid.
In general, the acids are reacted in proportions leading to a completely esterified pentaerythritol or trimethylolpropane with the preferred ester bases being the pentaerythritol tetraesters. Examples of such commercially available tetraesters include pentaerythritol tetracaproate, which is prepared from purified pentaery-thritol and crude caproic acid containing other C monobasic acids. Another suitable tetraester is prepared from a technical grade pentaerythritol and a mixture of acids comprising about percent valeric, 12 percent Z-methyl pentanoic, 27 percent caprylic, 15 percent pelargonic, 9 percent heptylic, 5 percent caproic and minor amounts of iso-valeric and capric acids. Another effective ester is the triester of trimethylolpropane in which the trimethylolpropane is esterified with a mono-basic acid mixture consisting of 2 percent valeric, 9 percent caproic, 13 percent heptanoic, 7 percent octanoic, 3 percent caprylic, percent pelargonic and 1 percent capric acids. Trimethylolpropane triheptanoate, trimethylolpropanepentanoate and trimethylolpropanehexanoate are also suitable.
ester bases.
The ester base comprises the major portion of the formulated synthetic ester-base lubricating oil composition. In general, this ester-base fluid is present in a concentration ranging from about to 98 percent of the composition.
The effectiveness of the lubricating oil compositions of the invention is enhanced by the addition of other additives to the oil composition. Alkyl or alkaryl phenyl naphthylamines are highly effective anti-oxidants for synthetic lubricating oils. These compounds are represented by the formula:
ditive is an amount from about 0.5 to 2.5 weight percent.
Another effective anti-oxidant for the lubricating oil composition of the invention is a dialkydiphenylamine represented by the formula:
in which R is an alkyl radical having from about four to 12 carbon atoms. Examples of these amines include dioctyldiphenylamine didecyldiphenylamine, didodecyldiphenylamine, dihexydiphenylamine and similar compounds. Dioctyldiphenylamine is the preferred compound and the preferred concentration is from about 0.5 to 2.0 percent.
An effective metal deactivator for a synthetic lubricating oil composition is a polyhydroxyanthraquinone. Suitable compounds in this class are the dior polyhydroxy-anthraquinones, such as 1,4-dihydroxyanthraquinone, also known as quinizarin, 1,5-dihydroxyanthraquinone and 1,S-di-hydroxyanthraquinone, and the higher polyhydroxyanthraquinones. The preferred concentration of this component is from about 0.01 to 0.5 weight percent.
A valuable anti-wear component for a synthetic lubricating oil composition is a hydrocarbylphosphate ester, represented by the formula (RO) -,PO, in which R is a hydrocarbyl radical having from two to 12 carbon atoms. The hydrocarbyl radical can be an alkyl, aryl, alkaryl, cycloalkyl or aralkyl radical of the prescribed carbon chain length, although radicals having from four to 8 carbon atoms are preferred. Effective compounds include tricresyl phosphate, cresyl di-phenyl phosphate, triphenylphosphate, tributylphosphate, tris- (2-ethylhexyl) phosphate and tricyclohexylphosphate. These compounds are generally employed in a lubricating oil composition in a concentration ranging from about 0.5 to 5 percent.
It is conventional to employ minor amounts of an anti-foam additive in the synthetic lubricating oil composition. Effective anti-foamants are the silicone fluids, such as dimethyl silicone and diethylsilicone and these are generally employed at a concentration ranging from about 5 to 200 ppm parts per million.
The lubricating oil composition of the invention was tested for its load-carrying properties in the Ryder Gear Test. This test was conducted in accordance with Federal Test Method Standard 791, Test Method 6508. The base fluid blend employed for conducting the tests consisted of a commercial ester base from pentaerythritol and a mixture of C to C fatty acids containing 0.10 weight percent quinizarin, 1.00 weight percent p,- p'-di-tert.-octyldiphenylamine, 1.50 weight percent N- (4-tert.-octylphenyl)-l-naphthylamine, 2.00 weight percent tricresyl phosphate and 50 ppm of a dimethyl silicone fluid.
The results of the Ryder Gear Test are given in Table I below:
TABLE I RYDER GEAR LOAD-CARRYING TEST Blend Identification 2 Example! 0.15 3325 3 Example 11 0.20 3560 4 Example lll 0.15 2560 5 Example IV 0.3 3155 6 Example V 0.3 2930 Runs 2, 3, 5 and 6 demonstrate that the novel synthetic ester-base lubricating oil compositions containing the prescribed thio-oxazolidinedione and thiazolidinedione and the corresponding amine salts of the invention possess substantially improved load-carrying properties as compared to both the Base Blend and to the fully formulated fluid of Run 4. Run 4 illustrates that the all-oxygen analog of Example 111 is totally ineffective as a load-carrying additive in these lubricants.
We claim:
1. A synthetic lubricating oil composition comprising a major portion of an aliphatic ester-base oil having lubricating properties formed from the reaction of a pentaerythritol or trimethylolpropane and a saturated hydrocarbyl monocarboxylic acid having from about 2 to 18 carbon atoms per molecule containing from about 0.01 to 5 weight percent of an oxazolidinedione, thiazolidinedione or the corresponding amine salt represented by the formulas:
in which X represents S when Y is O, and X represents 0 when Y is S and R represents a hydrocarbyl radical having from about four to 24 carbon atoms.
2. A lubricating oil composition according to claim 1 in which R represents an aliphatic hydrocarbon radical having from about 12 to 22 carbon atoms.
3. A lubricating oil composition according to claim 1 containing from about 0.05 to 0.5 weight percent of said thio-oxazolidinedione, thiazolidinedione or corresponding amine salt.
4. A lubricating oil composition according to claim 1 in which R is a t-C -C primary alkyl radical.
5. A lubricating oil composition according to claim 1 containing 2-thio-oxazolidinedione.
6. A lubricating oil composition according to claim 1 containing a 2,4-thiazolidinedione.
7. A lubricating oil composition according to claim 1 containing the tC, C primary amine salt of 2,4- thiazolidinedione.
8. A lubricating oil composition according to claim 1 containing the tC, C alkyl primary amine salt of 2-thio-oxazolidinedione.
9. A lubricating oil composition according to claim 1 containing from about 0.5 to 2.5 percent of an alkylphenyl naphthylamine, from about 0.5 to 2.0 percent of dialkyldiphenylamine, from about 0.01 to 0.5 percent of a polyhydroxyanthraquinone and from about 0.5 to 5 percent of a hydrocarbyl phosphate ester.
10. A lubricating oil composition according to claim 1 in which said ester-base oil is formed from the reaction of pentaerythritol and a mixture of C to C saturated fatty acids.
Claims (9)
- 2. A lubricating oil composition according to claim 1 in which R represents an aliphatic hydrocarbon radical having from about 12 to 22 carbon atoms.
- 3. A lubricating oil composition according to claim 1 containing from about 0.05 to 0.5 weight percent of said thio-oxazolidinedione, thiazolidinedione or corresponding amine salt.
- 4. A lubricating oil composition according to claim 1 in which R is a t-C18-C22 primary alkyl radical.
- 5. A lubricating oil composition according to claim 1 containing 2-thio-oxazolidinedione.
- 6. A lubricating oil composition according to claim 1 containing a 2,4-thiazolidinedione.
- 7. A lubricating oil composition according to claim 1 containing the t-C18-C22 primary amine salt of 2,4-thiazolidinedione.
- 8. A lubricating oil composition according to claim 1 containing the t-C18-C22 alkyl primary amine salt of 2-thio-oxazolidinedione.
- 9. A lubricating oil composition according to claim 1 containing from about 0.5 to 2.5 percent of an alkylphenyl naphthylamine, from about 0.5 to 2.0 percent of dialkyldiphenylamine, from about 0.01 to 0.5 percent of a polyhydroxyanthraquinone and from about 0.5 to 5 percent of a hydrocarbyl phosphate ester.
- 10. A lubricating oil composition according to claim 1 in which said ester-base oil is formed from the reaction of pentaerythritol and a mixture of C5 to C9 saturated fatty acids.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US28218272A | 1972-08-21 | 1972-08-21 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3779921A true US3779921A (en) | 1973-12-18 |
Family
ID=23080425
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US00282182A Expired - Lifetime US3779921A (en) | 1972-08-21 | 1972-08-21 | Synthetic aircraft turbine oil |
Country Status (1)
Country | Link |
---|---|
US (1) | US3779921A (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3901815A (en) * | 1974-06-05 | 1975-08-26 | Texaco Inc | Synthetic aircraft turbine oil |
US4179386A (en) * | 1978-05-30 | 1979-12-18 | Texaco Inc. | Synthetic aircraft turbine oil |
US4188298A (en) * | 1978-05-30 | 1980-02-12 | Texaco Inc. | Synthetic aircraft turbine oil |
US4216100A (en) * | 1978-08-03 | 1980-08-05 | Texaco Inc. | Pentaerythritol-fatty acid ester lubricant composition |
US4320018A (en) * | 1978-05-30 | 1982-03-16 | Texaco Inc. | Synthetic aircraft turbine oil |
US5322634A (en) * | 1991-09-16 | 1994-06-21 | Ford Motor Company | Electrorheological fluids comprising phenoxy organometallic salt particulate |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2796402A (en) * | 1953-11-16 | 1957-06-18 | Texas Co | Extreme pressure lubricant compositions |
US2796403A (en) * | 1953-11-16 | 1957-06-18 | Texas Co | Extreme pressure lubricant compositions |
US2796404A (en) * | 1953-11-16 | 1957-06-18 | Texas Co | Extreme pressure lubricant compositions |
US2800491A (en) * | 1954-12-14 | 1957-07-23 | Stauffer Chemical Co | Oxidation-resistant oleaginous materials |
US3249543A (en) * | 1963-04-30 | 1966-05-03 | Monsanto Res Corp | Lubricant composition containing a rhodanine compound |
GB1180387A (en) * | 1966-07-21 | 1970-02-04 | British Petroleum Co | Synthetic Lubricants for Aero Gas Turbines |
-
1972
- 1972-08-21 US US00282182A patent/US3779921A/en not_active Expired - Lifetime
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2796402A (en) * | 1953-11-16 | 1957-06-18 | Texas Co | Extreme pressure lubricant compositions |
US2796403A (en) * | 1953-11-16 | 1957-06-18 | Texas Co | Extreme pressure lubricant compositions |
US2796404A (en) * | 1953-11-16 | 1957-06-18 | Texas Co | Extreme pressure lubricant compositions |
US2800491A (en) * | 1954-12-14 | 1957-07-23 | Stauffer Chemical Co | Oxidation-resistant oleaginous materials |
US3249543A (en) * | 1963-04-30 | 1966-05-03 | Monsanto Res Corp | Lubricant composition containing a rhodanine compound |
GB1180387A (en) * | 1966-07-21 | 1970-02-04 | British Petroleum Co | Synthetic Lubricants for Aero Gas Turbines |
Non-Patent Citations (1)
Title |
---|
Cohen Ind. Eng. Chem. Vol. 45 (1953), pages 1766 1774. * |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3901815A (en) * | 1974-06-05 | 1975-08-26 | Texaco Inc | Synthetic aircraft turbine oil |
US4179386A (en) * | 1978-05-30 | 1979-12-18 | Texaco Inc. | Synthetic aircraft turbine oil |
US4188298A (en) * | 1978-05-30 | 1980-02-12 | Texaco Inc. | Synthetic aircraft turbine oil |
US4320018A (en) * | 1978-05-30 | 1982-03-16 | Texaco Inc. | Synthetic aircraft turbine oil |
US4216100A (en) * | 1978-08-03 | 1980-08-05 | Texaco Inc. | Pentaerythritol-fatty acid ester lubricant composition |
US5322634A (en) * | 1991-09-16 | 1994-06-21 | Ford Motor Company | Electrorheological fluids comprising phenoxy organometallic salt particulate |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US3720612A (en) | Synthetic ester lubricating oil compositions | |
US3931023A (en) | Triaryl phosphate ester functional fluids | |
US3224971A (en) | Borate esters and lubricant compositions containing said esters | |
US2962531A (en) | 3, 5-dialkyl-4-hydroxy benzylamines | |
US3869394A (en) | Lubricant composition and method | |
US4320018A (en) | Synthetic aircraft turbine oil | |
US3850824A (en) | Synthetic aircraft turbine oil | |
US3476685A (en) | Synthetic lubricating composition | |
US4226732A (en) | Synthetic aircraft turbine oil | |
US3697427A (en) | Lubricants having improved anti-wear and anti-corrosion properties | |
US3779921A (en) | Synthetic aircraft turbine oil | |
US3951973A (en) | Di and tri (hydrocarbylammonium) trithiocyanurate | |
US3779919A (en) | Synthetic aircraft turbine oil | |
US4157971A (en) | Synthetic aircraft turbine oil | |
US4064059A (en) | Synthetic aircraft turbine oil | |
US4096078A (en) | Synthetic aircraft turbine oil | |
US4189388A (en) | Synthetic aircraft turbine oil | |
US2836565A (en) | Lubricating compositions | |
US3799876A (en) | Corrosion inhibiting lubrication method | |
US4157970A (en) | Synthetic aircraft turbine oil | |
US4141845A (en) | Synthetic aircraft turbine oil | |
US3642632A (en) | Anthranilic acid esters as lubricant additives | |
US3901815A (en) | Synthetic aircraft turbine oil | |
US4124514A (en) | Synthetic aircraft turbine lubricating oil compositions | |
US4119551A (en) | Synthetic aircraft turbine lubricating oil compositions |